Summer vacation is here, and the whole gang heads out to Ami’s summer home for a beach vacation! Taiga and Ryuuji hatch a plan to scare Minori out of her wits so Ryuuji can swoop in and come to her rescue. However, when Kitamura overhears the cunning scheme, he demands to be let in on the action and drags Ami along for the ride. What soon follows is a trip into madness as the kids venture into a small cave by the beach where untold horrors await...